Valokuvakalvo

Valokuvakalvo, often referred to as photographic film, is a transparent strip coated with a light-sensitive emulsion. This emulsion typically contains silver halide crystals suspended in gelatin. When light strikes these crystals, it causes a chemical reaction, forming a latent image that is invisible to the naked eye. This latent image is then made visible through a process called development, which converts the exposed silver halide crystals into metallic silver.

Historically, photographic film was the primary medium for capturing images in cameras. It came in various types, differentiated by their sensitivity to light (ISO speed), color rendition, and grain structure. Color films use multiple layers of emulsion, each sensitive to different colors of light, to reproduce a full spectrum of colors. Black and white film, on the other hand, records only variations in brightness.

After exposure and development, the film negative can be used to create positive prints by exposing it to light through an enlarger onto photographic paper. Alternatively, some films, like slide film, are processed to produce direct positive transparencies intended for projection. The advent of digital photography has largely superseded the use of film for many applications, but film photography continues to be practiced by enthusiasts and professionals for its unique aesthetic qualities and artistic appeal. The chemical processes involved in film photography have also laid the groundwork for many other imaging technologies.